Lens comprising an adjustable focus length

1. A lens ( 1 ) for vision correction, wherein the lens ( 1 ) comprises:

a transparent base element ( 10 ) having a back side ( 12 ), and a front side ( 11 ) facing away from the back side ( 12 ),

a transparent and elastically expandable membrane ( 20 ) connected to said base element ( 10 ), wherein said membrane ( 20 ) comprises a back side ( 22 ) that faces said front side ( 11 ) of the base element ( 10 ),

a ring member ( 30 ) connected to said the membrane ( 20 ) so that the ring member ( 30 ) defines a curvature-adjustable area ( 23 ) of the membrane ( 20 ), and

wherein the lens ( 1 ) comprises a lens volume ( 41 ) adjacent said curvature-adjustable area ( 23 ) of the membrane ( 20 ), which lens volume ( 41 ) is delimited by the ring member ( 30 ), and wherein the lens ( 1 ) comprises a reservoir volume ( 42 ) arranged in a boundary region ( 24 ) of the lens ( 1 ), wherein said two volumes ( 41 , 42 ) are each filled with a transparent liquid ( 50 , 50 a , 50 b ), and

a pumping means ( 700 ) configured to transfer transparent liquid ( 50 ) from the reservoir volume ( 42 ) to the lens volume ( 41 ) or vice versa such that the curvature of said curvature-adjustable area ( 23 ) of the membrane ( 20 ) changes and the focal length of the lens ( 1 ) changes, characterized in that

the pumping means ( 700 ) comprises or is formed as at least a first electro-osmotic pump ( 170 ), which first electro-osmotic pump comprises a porous membrane ( 173 ), a first electrode ( 171 ), and a second electrode ( 172 ), wherein the porous membrane ( 173 ) is arranged between said electrodes ( 171 , 172 ) respectively.

2. The lens according to claim 1 , characterized in that the lens ( 1 ) further comprises a protecting means ( 31 ; 75 ; 33 ; 34 ) that is configured to reduce or prevent an effect of an eyelid of the user on said focal length when said eyelid rests on said boundary region ( 24 ) of the lens ( 1 ).

3. The lens according to claim 2 , characterized in that said protecting means ( 31 ; 75 ; 33 ; 34 ) is a rigid support structure ( 31 ) that is configured to reduce or prevent compression of the reservoir volume ( 42 ) when an eyelid of the user rests on said boundary region ( 24 ) of the lens.

4. Lens according to claim 3 , characterized in that said support structure ( 31 ) comprises a plurality of ridges ( 32 ).

5. Lens according to claim 4 , characterized in that said ridges ( 32 ) divide the reservoir volume ( 42 ) into a plurality of separate sectors ( 420 ), wherein each sector ( 420 ) is arranged between two neighboring ridges ( 32 ).

6. Lens according to one of the claim 3 , characterized in that said support structure ( 31 ) comprises a rigid top ( 34 ) covering the reservoir volume ( 42 ) at least in sections from above and a rigid bottom ( 33 ) covering the reservoir volume ( 42 ) at least in sections form below.

7. The lens according to claim 2 , characterized in that said protecting means of the lens ( 1 ) comprises at least one valve ( 75 ) for closing and opening a flow connection between the reservoir volume ( 42 ) and the lens volume ( 41 ).

8. The lens according to claim 2 , characterized in that the lens ( 1 ) comprises at least one reservoir channel ( 422 ) forming part of the reservoir volume ( 42 ), via which reservoir channel ( 422 ) the reservoir volume ( 42 ) can be fluidly connected to the lens volume ( 41 ).

9. The lens according to claim 8 , characterized in that the pumping means ( 700 ) comprises a ring-shaped actuator element ( 701 ), preferably in the form of a Piezo element ( 701 ), which is configured to be actuated such that liquid residing in the reservoir volume ( 42 ) is pressed into the lens volume ( 41 ), wherein said actuator element ( 701 ) is configured to expand outwards in a radial direction (R) running perpendicular an optical axis (z) of the lens ( 1 ) when being actuated, such that said actuator element ( 701 ) compresses a circumferential reservoir section ( 421 ) of the reservoir volume ( 42 ), which circumferential reservoir section ( 421 ) is fluidly connected to the lens volume ( 41 ) via the at least one reservoir channel ( 422 ), so as to push liquid from the reservoir volume ( 42 ) into the lens volume ( 41 ).

10. The lens according to claim 8 , characterized in that the actuator elements ( 701 ) are arranged along the at least one reservoir channel ( 422 ) and are configured to bend towards the at least one reservoir channel ( 422 ) when being actuated so as to compress the at least one reservoir channel ( 422 ) upon bending of the respective actuator element ( 701 ) such that liquid ( 50 ) is pushed from the reservoir volume ( 42 ) into the lens volume ( 41 ).

11. The lens according to claim 8 , characterized in that reservoir volume ( 42 ) comprises at least one chamber ( 426 ) that is connected via the at least one reservoir channel ( 422 ) to the lens volume ( 41 ), wherein the pumping means ( 700 ) comprises at least one actuator element ( 701 ), preferably in the form of a Piezo element ( 701 ), which is configured to bend towards the chamber ( 426 ) when being actuated so as to compress the chamber ( 42 ) upon bending of the respective actuator element ( 701 ) such that liquid ( 50 ) is pushed from the chamber ( 424 ) into the lens volume ( 41 ).

12. The lens according to claim 2 , characterized in that the pumping means ( 700 ) comprises a plurality of actuator elements ( 701 ), preferably in the form of Piezo elements ( 701 ), which are configured to be actuated such that liquid ( 50 ) residing in the reservoir volume ( 42 ) is pressed into the lens volume ( 41 ) or vice versa.

13. The lens according to claim 12 , characterized in that the actuator elements ( 701 ) are arranged along the at least one reservoir channel ( 422 ) and are configured to press against a deformable wall ( 423 ) of the at least one reservoir channel ( 422 ) so as to push liquid ( 50 ) from the reservoir volume ( 42 ) into the lens volume ( 41 ).

14. The lens according to claim 12 , characterized in that the actuator elements ( 701 ) are formed as ring-shaped Piezo elements which are coaxially arranged with respect to the optical axis (z) of the lens ( 1 ), wherein the Piezo elements are arranged radially further out than an outermost edge of the lens volume.

15. The lens according to claim 14 , characterized in that said actuator elements ( 701 ) are configured to expand in an axial direction coinciding with said optical axis (z) when being actuated, such that said actuator elements ( 701 ) press against a deformable wall ( 423 ) of the at least one reservoir channel ( 422 ) so as to push liquid from the reservoir volume ( 42 ) into the lens volume ( 41 ).

16. The lens according to claim 14 , characterized in that said actuator elements ( 701 ) are configured to expand in a radial direction (R) running perpendicular to said optical axis (z) when being actuated, such that said actuator elements ( 701 ) deform a deformable wall ( 423 ) of the at least one reservoir channel ( 422 ) so as to push liquid from the reservoir volume ( 42 ) into the lens volume ( 41 ).

17. Lens according to claim 1 , characterized in that the pumping means ( 700 ) comprises an actuator means ( 70 ) that is configured to press liquid ( 50 ) from the reservoir volume ( 42 ) into the lens volume ( 41 ) or vice versa.

18. Lens according to claim 17 , characterized in that the actuator means ( 70 ) is configured to compress at least one of said sectors ( 420 ), a selection of said sectors ( 420 ), or all of said sectors ( 420 ), so as to transfer liquid ( 50 ) from the respective sector ( 420 ) into the lens volume ( 41 ).

19. Lens according to claim 17 , characterized in that the actuator means ( 70 ) is configured to compress the individual sector ( 420 ) continuously so as to adjust said focal length in a continuous fashion, or that the actuator means ( 70 ) is configured to compress the individual sector ( 420 ) at once so as to adjust said focal length in a discrete manner.

20. The lens according to claim 17 , characterized in that the actuator means ( 70 ) comprises a plurality of first electrodes ( 71 ) each being attached to an associated first wall ( 200 ) and a corresponding number of second electrodes ( 72 ) each being attached to an associated second wall ( 100 ) such that pairs of first and second electrodes ( 71 , 72 ) are formed in each sector ( 420 ), wherein each pair of electrodes ( 71 , 72 ) delimits an associated gap ( 74 ) arranged between the respective first and second electrode ( 71 , 72 ) in the respective sector ( 420 ), which associated gap ( 74 ) is closable by means of a voltage applied to the respective pair of electrodes such that, when the respective gap ( 74 ) is closed, liquid ( 50 ) is pressed from the respective sector ( 420 ) into the lens volume ( 41 ), and wherein, when the voltage applied to the respective pair of electrodes ( 71 , 72 ) is decreased or turned off, the respective gap ( 74 ) opens and a tension of the membrane ( 20 ) causes a corresponding amount of liquid ( 50 ) to flow back from the lens volume ( 41 ) into the respective sector ( 420 ) of the reservoir volume ( 42 ).

21. Lens according to claim 1 , characterized in that said sectors ( 420 ) are each delimited by a first wall ( 200 ) and a second wall ( 100 ) that faces the associated first wall ( 200 ), wherein the first walls ( 200 ) are preferably formed by the membrane ( 20 ), and wherein the second walls ( 100 ) are preferably formed by the base element ( 10 ) or by the support structure ( 31 ).

22. The lens according to claim 1 , characterized in that the transparent liquid residing in the lens volume ( 41 ) is a hydrophobic liquid ( 50 a ), and wherein the liquid residing in the reservoir volume ( 42 ) is a hydrophilic liquid ( 50 b ) such that in each sector ( 420 ) an interface ( 50 c ) is formed between the hydrophilic liquid ( 50 a ) and the hydrophobic liquid ( 50 b ), wherein the pumping means ( 700 ) is configured to apply a voltage between the hydrophilic liquid ( 50 b ) residing in the respective sector ( 420 ) and a surrounding electrode ( 425 a ) embedded in a wall ( 425 ) enclosing the respective sector ( 420 ), wherein said electrode ( 425 a ) is electrically insulated towards the hydrophilic liquid ( 50 b ), such that the respective interface ( 50 c ) is moved towards the lens volume ( 41 ) thus pushing hydrophobic liquid ( 50 a ) into the lens volume ( 41 ) such that the curvature of said curvature-adjustable area ( 23 ) of the membrane ( 20 ) increases and the focal length of the lens decreases, wherein when said voltage is decreased or turned off, a tension of the membrane ( 20 ) causes a corresponding amount of hydrophobic liquid ( 50 a ) to flow back from the lens volume ( 41 ) into the reservoir volume ( 42 ).

23. The lens according to claim 22 , characterized in that the sectors ( 420 ) are in flow connection with each other by means of a circumferential reservoir section ( 421 ) formed by the reservoir volume ( 42 ), wherein said reservoir section ( 421 ) comprises a meandering shape at least in sections.

24. The lens according to claim 1 , characterized in that the lens ( 1 ) comprises a sensor means ( 80 ), a processing unit ( 90 ), a battery ( 110 ), and an actuator ( 70 ).

25. The lens according to claim 1 , characterized in that the lens ( 1 ) comprises a sensor means ( 80 ) configured to sense a signal, preferably in the form of a movement of the person wearing the lens ( 1 ), and to provide an output signal in response to said signal, wherein particularly said movement is a movement of one of: a crystalline lens, an eyelid ( 4 ), or of an eye ( 2 ) of said person.

26. The lens according to claim 25 , characterized in that the lens ( 1 ) further comprises a processing unit ( 90 ) that is configured to control the pumping means ( 700 ) and/or said at least one valve ( 75 ), so as to transfer liquid ( 50 ) from the reservoir volume into the lens volume or vice versa in response to the output signal provided by the sensor ( 80 ) or in response to an output signal provided by an external device ( 81 ).

27. The lens according to claim 1 , characterized in that the ring member ( 30 ) includes one or multiple channels ( 60 ) which fluidly connect the reservoir volume ( 42 ) and the lens volume ( 41 ).

28. The lens according to claim 1 , characterized in that the first and/or the second electrode comprise or are formed out of one of the following materials: carbon nanotubes, carbon black, carbon grease, conducting greases, metal ions, liquid metals, metallic powders, in particular metallic nanoparticles, metal films, or conducting polymers.

29. The lens according to claim 1 , characterized in that an anti-stiction coating or layer is provided on at least one of: the first wall, the second wall, the first electrodes, the second electrodes.

30. Lens according to claim 1 , characterized in that said first electro-osmotic pump ( 170 ) separates ( 170 ) an upper compartment ( 174 ) of the reservoir volume ( 42 ) from a lower compartment ( 175 ) of the reservoir volume ( 42 ), which compartments ( 174 , 175 ) are arranged on top of one another, wherein the upper compartment ( 174 ) is arranged between said first electro-osmotic pump ( 170 ) and said membrane ( 20 ); or that said porous membrane ( 173 ) separates ( 170 ) an upper compartment ( 174 ) of the reservoir volume ( 42 ) from a lower compartment ( 175 ) of the reservoir volume ( 42 ), which compartments ( 174 , 175 ) are arranged on top of one another, wherein the upper compartment ( 174 ) is arranged between said porous membrane ( 173 ) and said membrane ( 20 ).

31. Lens according to claim 30 , characterized in that said first electro-osmotic pump ( 170 ) is configured to pump liquid ( 50 ) from the upper compartment ( 174 ) into the lower compartment ( 175 ) or from the lower compartment ( 175 ) to the upper compartment ( 174 ) depending on a voltage applied to said electrodes ( 171 , 172 ) so as to transfer liquid ( 50 ) between the lens volume ( 41 ) and the reservoir volume ( 42 ).

32. Lens according to claim 30 , characterized in that the lower compartment ( 175 ) or the upper compartment ( 174 ) is connected to the lens volume ( 41 ) via at least one channel ( 177 ).

33. The lens according to claim 30 , characterized in that the lens ( 1 ) comprises a further ring member ( 300 ) surrounding the upper compartment ( 174 ), wherein said first electro-osmotic pump ( 170 ) is connected to a lower face side ( 30 c ) of the ring member ( 30 ) and/or to a lower face side ( 300 c ) of the further ring member ( 300 ).

34. The lens according to claim 30 , characterized in that the lens ( 1 ) comprises a support structure ( 182 ) arranged in the lower compartment ( 175 ) for supporting said first electro-osmotic pump ( 170 ) or said porous membrane ( 173 ), and/or a support structure ( 181 ) arranged in the upper compartment ( 174 ) for supporting said first electro-osmotic pump ( 170 ) or said porous membrane ( 173 ).

35. The lens according to claim 30 , characterized in that the base element ( 10 ) comprises a recess ( 10 a ), wherein said lower compartment ( 175 ) is arranged in said recess ( 10 a ), wherein particularly said recess ( 10 a ) is a curved and/or circumferential recess ( 10 a ).

36. The lens according to claim 35 , characterized in that the recess ( 10 a ) comprises two opposing steps ( 10 b ) for aligning said first electro-osmotic pump ( 170 ) with respect to the recess ( 10 a ).

37. Lens according to claim 1 , characterized in that said first electro-osmotic pump ( 170 ) is arranged adjacent a lateral surface ( 30 a ) of the ring member ( 30 ), which lateral surface ( 30 a ) connects an upper face side ( 30 b ) of the ring member ( 30 ), via which upper face side ( 30 b ) the ring member ( 30 ) is connected to the membrane ( 20 ), to a lower face side ( 30 c ) of the ring member ( 30 ), which lower face side ( 30 c ) faces away from said upper face side ( 30 b ).

38. Lens according to claim 1 , characterized in that said first electro-osmotic pump ( 170 ) is connected to a lower face side ( 30 c ) of the ring member ( 30 ), which lower face side ( 30 c ) faces away from an upper face side ( 30 b ) of the ring member ( 30 ), via which upper face side ( 30 b ) the ring member ( 30 ) is connected to said membrane ( 20 ).

39. The lens according to claim 1 , characterized in that said first electro-osmotic pump ( 170 ) comprises a first contact lead ( 171 a ) for connecting a battery ( 110 ) to the first electrode ( 171 ), and a second contact lead ( 172 a ) for connecting said battery ( 110 ) to the second electrode ( 172 ).

40. The lens according to claim 1 , characterized in that the first electro-osmotic pump ( 170 ) comprises a curved shape.

41. The lens according to claim 1 , characterized in that the base element ( 10 ) comprises a circumferential step ( 10 c ) for aligning the ring member ( 30 ) with respect to the base element ( 10 ).

42. The lens according to claim 1 , characterized in that the lens comprises a battery ( 110 ).

43. The lens according to claim 42 , characterized in that the battery ( 110 ) is arranged outside the lower and upper compartments ( 174 , 175 ), or that the battery ( 110 ) is arranged in the lower compartment ( 175 ).

44. The lens according to claim 42 , characterized in that the lens ( 1 ) comprises a power interface ( 185 ) configured for inductive charging of the battery ( 110 ).

45. The lens according to claim 44 , characterized in that the lens ( 1 ) comprises a processing unit ( 190 ) configured to control the first electro-osmotic pump ( 170 ) depending on said control signal of a sensor assembly ( 80 ) and/or depending on a control signal in the form of a modulated power supply signal received by said power interface ( 185 ).

46. The lens according to claim 44 , characterized in that the power interface ( 185 ), a sensor assembly ( 80 ), and a processing unit ( 190 ) are mounted to the ring member ( 30 ).

47. The lens according to claim 44 , characterized in that the power interface ( 185 ), a sensor assembly ( 80 ) and a processing unit ( 190 ) are mounted on a carrier ( 186 ), wherein the ring member ( 30 ) is also mounted on the carrier ( 186 ) or is formed by the carrier ( 186 ).

48. The lens according to claim 1 , characterized in that the lens ( 1 ) comprises a sensor assembly ( 80 ) configured to detect one of: an eye lid movement, a fully closed eyelid, a partially closed eye lid and to generate a corresponding control signal.

49. The lens according to claim 1 , characterized in that the lens ( 1 ) comprises a second electro-osmotic pump ( 270 ), which second electro-osmotic pump ( 270 ) comprises a porous membrane ( 273 ), a first electrode ( 271 ), and a second electrode ( 272 ), wherein the porous membrane ( 273 ) of the second electro-osmotic pump ( 270 ) is arranged between said electrodes ( 271 , 272 ) of the second electro-osmotic pump ( 270 ) respectively.

50. Lens according to claim 49 , characterized in that said second electro-osmotic pump ( 270 ) separates a further upper compartment ( 274 ) of the reservoir volume ( 42 ) from a further lower compartment ( 275 ) of the reservoir volume ( 42 ), which further compartments ( 274 , 275 ) are arranged on top of one another, wherein the further upper compartment ( 274 ) is arranged between said second electro-osmotic pump ( 270 ) and said membrane ( 20 ); or that said porous membrane ( 273 ) of the second electro-osmotic pump ( 270 ) separates a further upper compartment ( 274 ) of the reservoir volume ( 42 ) from a further lower compartment ( 275 ) of the reservoir volume ( 42 ), which further compartments ( 274 , 275 ) are arranged on top of one another, wherein the further upper compartment ( 274 ) is arranged between said porous membrane ( 273 ) and said membrane ( 20 ).

51. Lens according to claim 50 , characterized in that said second electro-osmotic pump ( 270 ) is configured to pump liquid ( 50 ) from the further upper compartment ( 274 ) into the further lower compartment ( 275 ), or from the further lower compartment ( 275 ) to the further upper compartment ( 274 ) depending on a voltage applied to said electrodes ( 271 , 272 ) of the second electro-osmotic pump ( 270 ), so as to transfer liquid ( 50 ) between the lens volume ( 41 ) and the reservoir volume ( 42 ).

52. Lens according to claim 50 , characterized in that the lens ( 1 ) comprises two opposing channels ( 177 ), wherein the lower compartments ( 175 , 275 ) or the upper compartments ( 174 , 274 ) of the two electro-osmotic pumps ( 170 , 270 ) are in fluid communication with the lens volume ( 41 ) via both channels ( 177 ).

53. Lens according to claim 52 , characterized in that the lens ( 1 ) comprises a support structure ( 183 a , 183 b ) arranged in each channel ( 177 ) for supporting the ring member ( 30 ) and/or said membrane ( 20 ).

54. Lens according to claim 1 , characterized in that the lens ( 1 ) is configured to be one of:

placed directly on the surface of an eye ( 2 ) of a person,

placed inside an eye ( 2 ) of a person,

placed in front of an eye ( 2 ) of a person, particularly spaced apart from said eye ( 2 ).

55. Optical assembly, comprising: a lens ( 1 ) according to claim 1 , and a transparent enclosure, wherein said lens ( 1 ) is arranged or embedded in said enclosure, and wherein preferably said enclosure forms or comprises a further lens.